Mally Johnson was 20 years old when Petroleum is discovered in Titusville, Pennsylvania leading to the world's first commercially successful oil well. Petroleum is a naturally occurring, yellow-to-black liquid found in geological formations beneath the Earth's surface. It is commonly refined into various types of fuels. Components of petroleum are separated using a technique called fractional distillation, i.e. separation of a liquid mixture into fractions differing in boiling point by means of distillation, typically using a fractionating column.